raw · papers · ingested 2026-07-02
Thermal-Responsive Smart Windows with Passive Dimming and Thermal Energy Storage (ACS Omega 2024)
confidence: high
Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC11209917/
Source: ACS Omega 2024 (open access via PMC11209917). Credibility: High (peer-reviewed, open access; the clearest index-matching numbers found).
Key points
- Index matching is the switch: liquid PCM (TD) n≈1.43, polymer matrix (PBB) n≈1.42 → melted state has no index step → 74.5% transmittance (“like ordinary glass”).
- Opacity when solid: crystalline TD stops matching the polymer → scattering interfaces; with dye, 0.2% transmittance at 25 °C.
- Supercooling/hysteresis (DSC): pure TD melt 35–42 °C / cryst 28–36 °C; polymer encapsulation widens to melt 27–49 / cryst 20–37. Dye adds heterogeneous nucleation sites → less supercooling, but dye particles scatter.
- Trade-off: more photothermal dye cuts clear-state transmittance 74.5% → 23.3%.
- Latent heat 161.9 J/g; photothermal efficiency 74.6%; stable ~1000 cycles.